Apparatus for dehydrating liquids



. June 12, 1928.

s. M. nlcK APPARATUS FOR DEHYDRATING LIQUIDS Filed oct. 22. 19204sneets-Sheet 1 [C75 /m/E/YTo-H.

June 12, 192s. 1,673,066

S. M. DICK APPARATUS FOR DEHYDRATING LIQUIDS Filed oct. 22. 1920 4sheets-sheet 5 WAM/WWMMMMWMM I v/.s /rrramvzns June 12, 192s. 1,673,066y

s. M. DICK APPARATUS FOR DEHYDRATING LIQUIDS Filed Oct. 22 1920 4Sheets-Sheet 4 l////// /l [Il [l Patented June. l2, 1928.

UNITED sTATEs PATENT OFFICE. i

SAMUEL M. DICK, or vivrrrmsaiOLrsy MINNEsOTAAssIGNOR To INTERNATIONALDRY MILK COMPANY, OF MINNEAPOLIS, MINNESOTA, A CORPORATION OF DELAWARE.

APPARATUS FOR DEHYDRATING LIQUIDS.

Application filed October 22, `1920. Serial No. 418,845.

My invention relates to apparatus in which the dehydration of milk vor`other liquids containing solids in solution is carried out by sprayingthe milk or other liquidin a chamber or cell, evaporating the Waterconstituents by subjecting the finely divided spray to a series oi.'heated Opposing air currents, carrying away the moisture therebyevapora-ted by r' moisture laden air from the cell and gravi tating thedryingsolids towards the bottom of the cell from which they arecollected .in

the form ot a dry powder.

` My invention relates more particularly to and is an improved andsimpliiied construction of the dehydrating cells shown and described inmy application dated Nov. 1 2, 1919, Serial No. 337,581 under Patent1,450,840, April 3, 1923, in which patent a double cell comprising aprimary condensing cell and a separate `powdering cell. is `re, quiredfor the complete carrying out of they dehydrating process. The Object ofAthe present invention i first: to produce a single dehydrating cell ofthe same general classin which a liquid like milk may be reduced to auniform dry powder in one passage through the cell` without any previouscondensation or other treatment. Second: to produce in this cell a wholemilk product or powder of a uniform quality in which the butterfatglobules will be encysted 'for preservation and protection and third:to `produce in the cell this Whole `milk product with encysted butterfat globules at a comparatively low telnperature and with a shortenedtime exposure of the milk to the evaporating air currents by which thebutter tat globules and other milk constituents willbe protected fromin- J li/l'y invention consists in the construction and combinations ofa cell as hereinafter described in the specification and illustrated inthe accompanying fdrawings, the novel features 0i the invention beingmore par-` ticularly pointed Outin the claims.

In the drawings, Figure lis a vertical section of a dehydrating cellembodying` my invention, the section being taken on the line 1--1 ofFigure 2,

Figure 2 is a horiozntal section on the line 2-2 of Figure 1,

exhausting the Figure 8 is a similar section `on the line 3-3 of `Figure1, i Figure 4 is a similarsection on the line 4--4 ot Figure 1.

Figure `5 is a similar section on the line .5-5 of Figure 1,

Figure 6 is a vertical diagonal section through the cell taken on theline 6-6 of Figures 2 and 1. i i

In carrying out my invention I provide a cell preferably ofoctagonalform in horizontal cross section as shown in the drawings although itmay be carried out ina cell that is circular, rectangular or other iiormin cross section. In constructing the cell lf divide it into toursuperimposed and merging zones, whichl Will denote consecutively A. B, Cand `D beginning from the topof the cell and which functionally may bedescribed as the upper mixing and evaporating Zone A, the exhaust ordead air zone B, the final drying or finishing Zone C and thereceivingand collecting zone D.

The upper zone Ais supported upon vertical posts 4. preferably by meansof cross girders 5, and is enclosed bv the octagonally arranged verticalwalls 6 and 7, and a ceiling orvupper floor 8.l This zone opens downwarddirectly into the exhaust zone B. Around the lowerouter portion of thezone A fl prefer to arrange a trough 9..

kThe exhaust ordead air Zone B is a.r

ranged between the upper `evaporating zone A, andthe finishing Zone C,and communi- Cates directly with both of these zones. Surrounding theupper portion of the cell comprising the Zones A and B is an air space iyor chamber 10 enclosed by the exterior Wall or walls 11, the ceiling`or upper Hoor 8,

which extends over suoli chamber, and a floorv 12. The chamber 10connects the exhaust zone B with the outer air through louvers 13 (seeFigure 1) which prevent swirling of the air as it leaves this chamberUli cell may be directly open to the chamber 10 without any form orenclosure, or may be enclosed 1n various skeleton forms, or with variousmaterials through which air will -freely pass. I prefer, however, toarrange a series of deflecting plates 14, radially around the centerofthe zone, supporting these plates in any suitable manner.

The zone C is preferably of greater diameter than the upper zone A, andthe de flecting plates 14, arranged between the zones A and C, arepreferably provided with the vertical inner edges and the sloping outerends, as shown in Figures 1 and 6 of 'the drawings. The plates 14 mayalso serve for the skeleton frame around and upon which suitable clothmaybe mounted to partially or entirely enclose the dead air zone B.

The zone C is enclosed by walls 6a and 7, in the lower part of which Ipreferably provide exhaust doors preferably covered with breathing cloththrough which air from this zone may have exit into a surroundingchamber 16,'enclosed by the walls-11 and floors 12 and 17. Openings 18provided with suitable trap doors 18a may be provided in the floor 12through which air may pass from the chamber 16 into the upper chamber l0and thence escape to the outer air through the louvers 13.

vThe lower or collecting zone D consists substantially of the spaceenclosed by the walls 6a and 7 below thel exhaust doors 1.5 andterminates at the collecting floor 20, which'forms the bottom closure ofthe cell. This floor preferably slants downward from the sides towardsthe center, where I preferably arrange a spiral conveyer 21 in atrough22, adapted to discharge the linished material into a suitable coolingand sifting 1nachine 23.

The collecting or receiving zone D projects a short space below theouter floor 17 surrounding the cell and forming the bottom of thechamber 16 and a series of openings 2Oa normally closed by-the doors orwindows 2Gb, are arrangedin the wall around the zone D just above thefloor 20. These doors, some of which may be provided with glass. throughwhich the interior of the cell may be observed by the attendant, openoutward when it is desired to clean the lloc-i1 2O or brush the materialcollected on this floor into the conveyor 21. Doors 11a are provided inthe surrounding walls 11 through which access may be had tothe chamber16 from the boiler room 19 and work room 19a and doors 11b, preferablyprovided with louvers, (not shown) are arranged in the walls 11 throughwhich access may be had to the trap doors 18 from the rooms 19c and 19d.

Air is supplied. to the cell from a fan or blower (not shown in thedrawing) preferably through air trunks 24 and 24 havingl main supplypipes 25 and 26,partially passing around the cell at the. lower portionof lthe finishingv zone C. From these vbranch pipes lead upwards aseries of conductors 27 the zone C of the cell.

and 28, respectively, preferably arranged in nozzles 29, passing throughthe walls 6a to l prefer to provide each vertical conductor with threenozzles 29, spaced-one above the other, at varying distances andarrangedwith each tier of nozzles opposite another' series extending through theopening through the walls of` the cell. rlhe nozzles are shown asarranged directly opposite each other, and while this is the preferredarrangement it not a necessary one and l do not limit myself thereto.Detween the members of each pair of conductors 27 and 28, lfpreferabiyarrange ver` tical ducts 30 and 81, passing from the main supply pipes25 and 26, and terminating above with the inwardly curved nozzles 82,leading to the upper evaporating or mixing zone A of the cell. fl haveshown a series of four nozzles, laid one above the other for each pipe8O andl'l and these preferably enter the cell at opposite sides of thezone through the cell walls 6. lnteri'nediate the zones A and C. and inthe dead air line space of the exhaust zone B, I preferably provideairshunts 30 and 31a controlled by a valve or damper 83 and leadinginwardly from the vertical air pipes and 81, through which any Vlightcurrent of air may be directed into the dead air space of the exhaustzone to warm the air in the dead air space and increase its humidityabsorbingproperties.

The milk is `delivered in regulated quantity from a supply pipeSilhaving a. control valve '34?, into the upper zone Aof the cell 1n aseries ofthm sheets or sprays produced by a suitablek centrifugalsprayer 35 mounted usually below the ceiling 8 at substantially l thecenter of the cell and driven by any suitable means, such as a'motor 86,belt 87 and pulley 38.

The air isl heated preferably before it enters the trunks, pipes' anddistributing con ductors above describedl and the'degree of temperaturevaries preferably with the quality of the liquid or its. solid contents,but is generally 'regulated to be higher for the lower zone C thanfortheulnier evaporat-v ing zone A. In the process" of dehydration ofmilk, the air enters tho upper zone A through the nozzles 32 fromopposite sides` of the cell and generally in currents directed towardsthe center of the cell, which some of the currents reach.` The heatedair immediately mixes lwith the finely divided or atomized spray of milkthrown from the centrifugal sprayer 35, and the hon'iogeneous mixture oftheheated air and atomized liquid causes a practically instantaneonsevaporation and the air takes up a maximum amount of moisture. Themoisture laden air and. milk constituents gravitate towards the exhaustor. deadair zone B there being no other exit from thezone A. iSimultaineously with the admission ol airito the zone A, a volume ofair, preferably heated to `a higher' temperature, is admitted to thelower finishing zone C tl'irough the nozzles Q9 and in a variety oidirections and velocities. This volume of heated air naturally risestowards the exhaust and deadvair zone B, Where it meets the fallingvolume of air from the upper zone A creating asubstantially neutral orcalm zone line through the horizontal center of the zone B.

From the zone B `the air from both, zones A and C then drifts outbetween the plates 14 through the large expansion chamber 10 in amovement so slow that currents are hardly preceptible, and reaches theouter air through the louvers 13. f By reason ot' the slow movements of`the air from the zone IB, the solids separated by evaporation readilyfall across the calm or neutral part-'ol the zone B and are then caughtand enveloped in thecyelical cross currents in the tinisl'iing zone C.Here the gravitati ng particles are retarded in their downward motion bythe great number of circular horizontal and vertical air currentsrolling and .moving the particles hither and thither until alll moistureis absorbed in the air and the fatty globules of the milk encysted inthe colloids ofthe skim milksolids and Whenthese accumulate sufficientWeight, they find their Way through the currents of air with theencysted fat globules and gravitate to the floor 20at the bottom of thecollecting zone D, from whence they are carried to the cooling andsifting machine 23 by the conveyer 21.

The air volume in the finishing zone C is generally admitted throughabout twice as many nozzles in the upper evaporating zone A, and at aconsiderable higher temperature, preferalily about 180 to 190 degrees F.It naturally has a general upwardly moving tendency, but the reductionol' temi perature caused by the rapid moisture evapo ration greatlyretards the upward movement of the air volume and as some o'l' the airmay escape through the aspirating cloth in the doors 15, and these doorsmay also be adjusted to be l'iartially or fully open during operation,the strength of the general up- Ward movement o'f the air volume in thefinishing cellv C may be accurately controlled to prevent solids 'frombeing carried outwards 'from the exhaust or dead air zone B, by causinga suficient part of the heavier moisture laden air to he drawn oft justabove the collecting cell D. The air thus Withdrawn through the doors 15enters the chamber 1G and its exit to the upper chamber `1O and outerair may he further controlled by the trap doors 18a. It the air passingupwards through the openings 18 should he closed and theair conducteddirect to the outside :trom thev finishing zone U through the doors, orlouvers 11b Without passing through the exhaust zone B. HoW- ever, itisvery desirable to have a considerable percentage oit the air from thefinishing zone pass out by way of the dead air zone, hence that zone isgenerally made large enough for the whole volume ot air coming intoyboth evaporating zones to pass out Ithrough itwvithout producing strongcurm rents or eddies. As further preventives oit solids drifting outthrough the dead air zone l, the lower linishing zone (lis of considerahly larger area in horizontal cross section and the radiallyarranged plates 14 sur rounding the zone ,l and projecting over thelowerzone C prevent swirling and eddying of the air as it leaves thedead air zone. The

plates lt also form a skeleton frame upon zone B. The trough 9 aroundthebottom ot the upper evaprniating zone A, the sidesI oif lwhichpreferably slant outwards so that the inner edge ofthe trough will notproject beyond the inner plane of the walls o of the zone, is `lor thepurpose of receiving any liquid, which may accidentally collect on theWalls of the cell during operation and to prevent the said liquid frompassing across the exhaust in drops to the linishing zone below. `Thedivision floors 12 and 17 serve the operators in caring for or drainingthis trough but principally for adjusting and rogulz'rting the How olair and the general functioning of the dehydrating apparatus, and theupper room 39 enclosed by the Walls 4.() and. roof /11 .is preferably agenera-l Work room 'for the attendants. It is evident that variousmodilications may be .made in the details of' construction withoutdeparting from the principle and scope of the invention and I do nottherefore limit the claims to the exact construction shown.

I claim as my invention:

1. A dehydrating cell comprising an upper liquid eva poratingcompartment closed at its top and With an opening in its bottom, n'ieans'lor introducing into the compartment the ma terial to he dried, a lowerdrying compartment closed at its bottom and with an opening in its top,means for directing air mirrents into both of said compartments, anintermediate compartment communicating with said compartments and havingexhaust openin in Vits sides through which-air from said upper and lowercompartment is exfill hausted, and means for exhausting air from saidlower compartment independently of said intermediate compartment, saidmeans including an outlet below the air admission inlets in the lowerchamber.

2. A dehydrating cell comprising an upper liquid spraying andevaporating compartment and having means for introducing thereintomaterial to be dried, a lower drying and inishing compartment, meansi'or directingv air currents into the sides of each of said compartmentsin opposite directions, anL intermediate exhaust compartment throughwhich the air from the upper and lower'compartmentmay he exhausted withradial air detlecting members surrounding said exhaust compartment.

A dehydrating apparatus comprising an outside casing, an evaporatingcompartment in the upper portion oi' the casing', an apparatus forspraying the material to be dried in said compartment, and a. lowerdrying and finishing compartment in the lower por tion ci the casingwith air inlets through the sides of both con'ipartments, andconnections tor conducting air into said compartments, a middlecompartment in open communication with said upper' and lower compartmentand having openings through `its sides communieating through said casingwith the outside air. l

4l. A dehydrating apparatus comprising an outer casing, an uppercompartment 1n the casing open at its bottom and having therein :idevice tor spraying the material to be ilried7 and ai lower compartmentalso in said casing open at its top, there being side air spaces betweenboth said compartments and the casing and a middle compartmentincommunication with both said upper and lower compartments having exhaustopenings at its sides communicating with the air space in the casing,said casing having air outlets therein, and means for conducting heatedair and introducing it through the sides of both upper and lowercompartments.

A dehydrating apparatus comprising an outer casing, an upper compartmentopen at its lower end with apparatus therein for spraying the materialto be drieda. lower compartment with an opening atits upper end. therebeing an air space between both said compartments and the outer casing,a middle compartment between said upper and lower compartments and inlopen communication therewith, said middle compartment having exhaustopenings in its sides commu nicating with the air space inthe casing,said casing having air outlets, means for conducting heated air andintroducing it at oppositely disposed places in the sides of said upperand lower compartments, sai-d means also having controlled communicationwith said middle compartment.

In witness whereof, I have hereunto set my hand this 19th day ofOctober, 1920.

SAMUEL M; DICK.

